WO1988005423A1 - Platre aciculaire de type tabulaire et procede de fabrication de papier avec charge - Google Patents

Platre aciculaire de type tabulaire et procede de fabrication de papier avec charge Download PDF

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Publication number
WO1988005423A1
WO1988005423A1 PCT/US1988/000141 US8800141W WO8805423A1 WO 1988005423 A1 WO1988005423 A1 WO 1988005423A1 US 8800141 W US8800141 W US 8800141W WO 8805423 A1 WO8805423 A1 WO 8805423A1
Authority
WO
WIPO (PCT)
Prior art keywords
crystals
largest dimension
micrometers
tabular
gypsum
Prior art date
Application number
PCT/US1988/000141
Other languages
English (en)
Inventor
Norman E. Johnstone
John C. Gaynor
Robert W. Erickson
Original Assignee
United States Gypsum Company
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by United States Gypsum Company filed Critical United States Gypsum Company
Priority to DE8888902990T priority Critical patent/DE3878756T2/de
Priority to AT88902990T priority patent/ATE86231T1/de
Publication of WO1988005423A1 publication Critical patent/WO1988005423A1/fr
Priority to DK515588A priority patent/DK171467B1/da
Priority to FI884250A priority patent/FI92047C/fi
Priority to NO884146A priority patent/NO175494C/no

Links

Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
    • D21H21/50—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by form
    • D21H21/52—Additives of definite length or shape
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F11/00—Compounds of calcium, strontium, or barium
    • C01F11/46—Sulfates
    • C01F11/466—Conversion of one form of calcium sulfate to another
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H17/00—Non-fibrous material added to the pulp, characterised by its constitution; Paper-impregnating material characterised by its constitution
    • D21H17/63—Inorganic compounds
    • D21H17/67—Water-insoluble compounds, e.g. fillers, pigments
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/10—Particle morphology extending in one dimension, e.g. needle-like
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/54—Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer

Definitions

  • This invention relates to the manufacture of paper, and is particularly directed to the preparation and use of a mineral filler that is composed of tabular acicular crystals for the manufacture of paper. These crystals are of a shape reminiscent of a "tongue depressor stick" shape.
  • mineral fillers are incorporated with the pulp to improve such properties as color, opacitv and printability.
  • the fillers also allow the use of lessened amounts of cellulosic fiber in the pulp.
  • Typical levels of filler addition in acid sized papers range from about 5 to apout 12% by weight; but more recent alkaline sized papers can approacn filler levels of 20% or more, particularly if expensive retention aids are included.
  • large proportions of the fillers added to the pulp normally pass through the paper-making screens and are not retained in the paper web.
  • U. S. patent 848.916 discloses the addition of a thin paste of finely ground natural gypsum and water as a filler in paper making.
  • U. S. patent 105.591 discloses the addition of finely ground natural gypsum or sul furi c aci d preci pitate as paper f i l l er , and improved retention in the paper by using a sulfate saturated water with the finely divided powder.
  • U. S. patent 4,470,877 teaches dry particulate gypsum addition in paper making with significant amounts of polymeric resin latex binders and retention aids to overcome poor retention and strength reductions.
  • U. S. patents 3,822,340: 3,961,105 and 4,152,408 disclose other crystalline varieties of calcium sulfate in a whisker fiber form and suggest their use as reinforcing fiber in products such as paper.
  • Such whisker fiber materials are made from select materials under energy intensive autoclaving conditions witn extensive dewatering and drying.
  • British patent 1,528,165 and U. S. patent 4,270,954 describe the through-solution production o f very large and very long calcium sulfate dihydrate fibers having average length to diameter aspect ratios over 100:1 and lengths in the longest dimension of at least 0.2 millimeters for possible use in paper.
  • the fibers are obtained by a through-solution reaction, with complete calcium sulfate dissolution, under quiescent conditions over periods of time up to 16 hours. Such would be prohibitively expensive in an area of use where an increase of a few cents per pound over commonly available spheroidal particles of other minerals generally mitigates against an additive's usage.
  • U. S. patent 2,304,361 describes a process for preparing gypsum filled paper said to be in a more economical fashion in the sense that a part of the dilution water for paper making is used in preparing the calcium sulfate dihydrate slurry, and the slurry is fed to paper making without dewatering or drying the gypsum.
  • the gypsum crystals may have been considered "of a fiberous character " and "of long, needle-like masses" at the time ot that patent, this was in comparison to the then common alternative ot finely jround or powdered gypsum.
  • the process disclosed actually produces masses of extremely small needles due to a large amount at self-nucleation of the dihydrate during the crystalization. Such crystals are extremely tiny in comparison to subsequently developed whisker fibers and fiber forms of calcium sulfate dihydrate.
  • Another object is to provide an improvement in paper making wherein a gypsum filler presenting a generally different shape and size is added having much greater retention than small needle-shaped masses or spheroidal gypsum particles, and without the expensive production costs of the extremely long and slender whisker and fiber materials.
  • the obtained slurry of crystals have an aspect ratio of about 100:10:1 and bv count average length of about 100-450 micrometers (um) in the largest dimension of the particle and about 10-40 um in the second largest dimension.
  • the obtained slurry may be added to paper pulp at any point prior to web formation by drainage.
  • FIG. 1 is a scanning electron microscopic photograph of tabular acicular gypsum crystals of the invention.
  • FIG.2 is a scanning electron microscopic photograph of tiny needles of gypsum.
  • FIG. 3 graphically illustrates percent of dihydrate filler retention versus filler length in micrometers for various gypsum particles. Description of the Preferred Embodiments
  • the mineral filler of the present invention is prepared by hydrating calcium sulfate hemihydrate in a constant volume, seeded, continuously stirred (with gentle sweeping aditation) atmospheric presssure reactor under low levels of super-saturation, preferably using an about 20-25% by weight total solids slurry at about 50-60o C, to produce a tabular acicular configuration having a mean particle size in the largest dimension of the particles of about 100-450 um and about 10-40 um in the second largest dimension.
  • the produced particle slurry is classified, with the smaller particles recycled to the reactor while the larger particles are passed to the paper-making pulp.
  • the calcium sulfate hemihydrate reactant may be any of the commonly available commercial materials.
  • the hemihydrate may be ordinary plaster of Paris or kettle stucco which are forms of beta calcium sulfate hemihydrate, or it may be a form of alpha calcium sulfate hemihydrate also called alpha gypsum.
  • Such hemihydrates may be calcined from natural gypsum or derived from calcium suitates produced in various chemical processes such as from flue gas desulfurization products, citrogypsum, phosonogyosum and the like.
  • the reaction conditions in the present process may differ slightly due to peculiarities of the specific particular hemihydrate or gypsum source effecting differing rates of dissolution, reprecipitation or crystal habit.
  • the gypsum should be at about saturation in the reactor, with about 20-25%. total solids preferred. A low level of super-saturation is preferred for optimum crystal growth upon seed crystals without a lot of self-nucleation.
  • the rate of reaction is a function of the rates at which the nemihydrate first dissolves in the water and then precipitates upon existant gypsum crystals. If an undesired high level of super-saturation occurs, this diffusion controlled reaction will proceed at a rapid rate with homogeneous self-nucleation leading to a massive "blooming" of very tiny nucleii and little growth upon individual crystals. That leads to an almost gelling of masses of low micrometer sized tiny needle crystals characteristic of U. S. patent 2,304,361.
  • the temperature of reaction preferbly is from about 50o C to about 60o C.
  • the particular desired temperature may be maintained on each charge to the reactor by any convenient means such as direcrt or indirect heating means. steam injection. electrical heating elements and the like. Temperatures as low as 35oC and as man as 90oC may be used.
  • the total solids in the reactor may be from about 20% to about 25% by weight at the preferred operational temperatures to maintain a low level of super-saturation. Higher levels will lead to higher contact nucleation which leads to stubbier and blockier crystals.
  • FIG. 1 presents a scannino electron microscopic photograph showing the general configuration of tabular gypsum filler crystals of the invention.
  • Portions of samples 1 and 8 were selected tor further evaluation in paper making, with one aliguot of each sample added directly to a paper pulp and another aliguot classified before addition to the pulp.
  • the sample was passed througn a 50 mesh (300 um openings) sieve and then the portion retained on a 140 mesh (106 um openings) sieve was added to the pulp to give a dry fiber to filler ratio of 70:30 parts by weight.
  • the pulp comprised calcium sulfate saturated water mixed with dry fiber to form a 1.5% solids consistency pulp which was refined to 350 Canadian Standard Freeness.
  • the pulp dry fiber solids were 30% waste newspaper and 70% old corrugated box board.
  • the pulps were felted into single ply handsheets prepared according to TAPPI method T-205 on a standard 6-1/4 inch (159 mm) diameter sheet machine to produce 1.5 gram handsheets. Physical properties of the prepared handsheets are set forth in Table 2. Looking at Table 2, it is apparent that the samples with fines removed had better retention, even though in one case the classified particle size was lower in aspect ratio and more blocky in terms of average length in the longest dimension. Generally it had been heretofor believed that only more f i berous characteristics led to greater retention in paper formation.
  • Freshly calcined hemihydrate was charged in a 10% solids slurry to a batch stirred reactor equipped with a turbine mixer providing high speed, high shear mi ⁇ ing at 3000 rom. This reactor was maintained at 20-21oC. Within 10 minutes massive self-nucleation resulted in a blooming of very large numbers of tiny needle crystals having a by count average 11.3 micrometer length and aspect ratio of about 5:1 for Sample 11.
  • a 20% solids slurry of alpha hemihydrate (HYDROCAL B base hemihydrate) was fed into a seeded continuously stirred reactor crystallizer vessel of Example 1 maintained at 50oC. Seed material provided a location for crystal growth and minimized the extent of nucleation which in turn results in a larger crystal size and more uniform distribution. Optimum seed crystal size at the beginning of reaction appears to be in the area of 20 micrometers. After reaction for 15 minutes, platelet-like tabular crystals having a by count average particle size in the largest dimension of about 45 micrometers. 4-5 um in the next largest dimension, and thickness of 1-2 um were obtainedd. Samples 14 through 16 - Tabular ot about 100-200 um:
  • a flue gas desulfurization calcium sulfate dihydrate derived from a sulfur dioxide scrubbing operation was calcined to hemihydrate and around to a 10,400 square centimeters per gram Blame surface area.
  • a 20% solids slurry of this hemihydrate was fed to the crystallizer of Example 1 maintained at 60o C.
  • a tabular gypsum crystal slurry was obtained with a by count average particle size in the largest dimension of 127 micrometers. 10-50 um in the second largest dimension, and thickness of 1-3 um.
  • the hand sheets were also evaluated for fiber breaking length by TAPPI standard procedure T 220ps-71. Exemplary results are set forth in Table 3. Generally the smaller the decrease in paper breaking length in comparison to unfilled control handsheets. the stronger the hand sheet and the more filler may be added while maintaining minimum strength requirements.
  • nand sheets were evaluated for percent drop in porosity by TAPPI Useful Test Method 524. Exemplary results are also set forth in Table 3. It should be remembered in looking at these results that very fine parti cl es may fill in the pores between the matted fibers in contrast to l arger filler particles that bridge across the pores or openings between the matted fibers. The impact of this is that some tiny particles may give a false negative drop in porosity value, as in Sample 12.
  • crystal habit modifiers may be added during the preparation of the tabular crystals to emphasize crystal growth in the longest dimension.
  • mineral acids such as sulfuric acid may be added: and various halogen, sulfate or nitrate salts such as sodium chloride may be added to emphasize growth in the proper dimensions.
  • the tabular crystals of the invention can be advantagesously used as additions for the filling and/or improvement of mechanical properties of matrix materials of all kinds. Preferrably they are used for filling various papers such as coarse liner board paper or various orades of fine paper stock. Generally, the tabular crystals of the invention are of a white coloration depending upon the source and impurities in the starting calcium sulfate structure. Various decolorants, brighteners and the like may be added to improve whiteness and brightness if desired deoending upon the purposes of the paper pulp. The crystals may be used for example as filler in the manufacture also of plastics of all kinds.

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  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
  • Paper (AREA)
  • Crystals, And After-Treatments Of Crystals (AREA)
  • Compositions Of Oxide Ceramics (AREA)
  • Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
  • Table Devices Or Equipment (AREA)
  • Medicinal Preparation (AREA)
  • Glass Compositions (AREA)
  • Producing Shaped Articles From Materials (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
  • Electronic Switches (AREA)
  • Making Paper Articles (AREA)
  • Sheets, Magazines, And Separation Thereof (AREA)
  • Catching Or Destruction (AREA)
  • Elevator Door Apparatuses (AREA)

Abstract

On prépare une variété tabulaire d'une charge à base de cristaux de plâtre aciculaire en hydratant des particules de dihydrate de sulfate de calcium dans un réacteur continuellement remué à cristaux de précipitation dans un état de sursaturation de niveau faible, de façon à obtenir des cristaux ayant un rapport d'allongement d'environ 100:10:1 et une longueur moyenne dans le sens le plus long d'environ 100 à 450 micromètres. Lors de la fabrication du papier, la boue de cristaux tabulaires ainsi obtenue peut être directement ajoutée à la pâte à papier avant la formation de la bande, de façon à produire un papier chargé ayant une capacité élevée de rétention de la charge.
PCT/US1988/000141 1987-01-16 1988-01-11 Platre aciculaire de type tabulaire et procede de fabrication de papier avec charge WO1988005423A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
DE8888902990T DE3878756T2 (de) 1987-01-16 1988-01-11 Tafelfoermige gipsnadeln und verfahren zum fuellen von papier.
AT88902990T ATE86231T1 (de) 1987-01-16 1988-01-11 Tafelfoermige gipsnadeln und verfahren zum fuellen von papier.
DK515588A DK171467B1 (da) 1987-01-16 1988-09-15 Fremgangsmåde til fremstilling af tavle- og nåleformede gipskrystaller, navnlig til brug ved fremstilling af papir
FI884250A FI92047C (fi) 1987-01-16 1988-09-15 Menetelmä suurien levymäisten, neulamaisten kipsikiteiden valmistamiseksi
NO884146A NO175494C (no) 1987-01-16 1988-09-16 Fremgangsmåte for fremstilling av store gipskrystaller

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US004,545 1987-01-16
US07/004,545 US4801355A (en) 1987-01-16 1987-01-16 Tabular acicular gypsum and method of filling paper

Publications (1)

Publication Number Publication Date
WO1988005423A1 true WO1988005423A1 (fr) 1988-07-28

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PCT/US1988/000141 WO1988005423A1 (fr) 1987-01-16 1988-01-11 Platre aciculaire de type tabulaire et procede de fabrication de papier avec charge

Country Status (14)

Country Link
US (1) US4801355A (fr)
EP (1) EP0298120B1 (fr)
AT (1) ATE86231T1 (fr)
AU (1) AU605576B2 (fr)
CA (1) CA1307903C (fr)
DE (1) DE3878756T2 (fr)
DK (1) DK171467B1 (fr)
ES (1) ES2005755A6 (fr)
FI (1) FI92047C (fr)
MX (1) MX165337B (fr)
NO (1) NO175494C (fr)
NZ (1) NZ223170A (fr)
WO (1) WO1988005423A1 (fr)
ZA (1) ZA88264B (fr)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989009187A1 (fr) * 1988-03-24 1989-10-05 Platres Lafarge S.A. Procede de preparation de sulfate de calcium a structure cristalline longiligne dotee d'une longueur et d'un facteur de forme maitrises
FR2640961A1 (fr) * 1988-12-22 1990-06-29 Lafarge Platres
EP0663374A1 (fr) * 1994-01-14 1995-07-19 USG INTERIORS, Inc. Une composition pour dalle acoustique sans laine minérale
EP0692456A1 (fr) 1994-07-15 1996-01-17 Compania General Yesera, S.A. Procédé d'obtention d'une charge radiale, destinée en particulier à l'industrie papétière, charge obtenue formée de sulfate de calcium anhydre et hémihydrate et composition utile pour préparer cette charge
WO2008092990A2 (fr) * 2007-02-02 2008-08-07 Kemira Oyj Produit de type gypse et procédé pour la préparation de celui-ci
WO2010151499A1 (fr) * 2009-06-22 2010-12-29 Hercules Incorporated Revêtement à germe cristallin pour parement de panneau mural en gypse
WO2011098672A1 (fr) 2010-02-10 2011-08-18 Kemira Oyj Procédé pour la préparation d'un composite pigment‑fibre
WO2011141632A1 (fr) 2010-05-10 2011-11-17 Kemira Oyj Produit composite de gypse-fibre

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5106600A (en) * 1987-01-16 1992-04-21 United States Gypsum Company Process for producing tabular acicular gypsum crystals
FR2647433B1 (fr) * 1989-05-23 1991-10-31 Lafarge Coppee Da Procede de preparation par voie aqueuse de sulfate de calcium purifie
US6399185B1 (en) * 1998-10-30 2002-06-04 Timothy D. Cathey Vegetation substrate
CA2367593C (fr) * 2001-08-13 2003-02-18 Kruger Inc. Methode pour reduire la solubilite du sulfate de calcium dihydrate dans une suspension aqueuse et methode de preparation
US7273579B2 (en) * 2004-01-28 2007-09-25 United States Gypsum Company Process for production of gypsum/fiber board
US8226766B2 (en) 2010-12-22 2012-07-24 United States Gypsum Company Set accelerator for gypsum hydration

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1962887A (en) * 1931-02-07 1934-06-12 American Cyanamid Co Method of controlling crystal size
US3594123A (en) * 1967-08-10 1971-07-20 Arizona Chem Enhancement of gypsum crystal growth in wet-process phosphoric acid
US3627485A (en) * 1968-11-05 1971-12-14 Nippon Kokan Kk Method of producing calcium sulfate dihydrate
US4270954A (en) * 1976-05-14 1981-06-02 Suddeutsche Kalkstickstoff-Werke Aktiengesellschaft Inorganic fibers
US4470877A (en) * 1981-05-13 1984-09-11 United States Gypsum Company Paper having calcium sulfate mineral filler for use in the production of gypsum wallboard

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US105594A (en) * 1870-07-19 Improvement in the manufacture of paper
US848916A (en) * 1907-01-18 1907-04-02 Alfred Monin Loading or filling substance for use in the manufacture of paper.
US1751429A (en) * 1927-06-20 1930-03-18 Canada Gypsum And Alabastine L Reenforced building material and process of making the same
US2235531A (en) * 1931-09-04 1941-03-18 West Virginia Pulp & Paper Com Method of producing paper filler
US2304361A (en) * 1938-10-31 1942-12-08 Howard D Meincke Method of making paper
US2530986A (en) * 1944-08-12 1950-11-21 Moses Edmund Quincy Plaster of paris containing paper and method of making
US3822340A (en) * 1972-03-27 1974-07-02 Franklin Key Calcium sulfate whisker fibers and the method for the manufacture thereof
US3961105A (en) * 1972-03-27 1976-06-01 Certain-Teed Products Corporation Method for the manufacture of coated calcium sulfate whisker fibers
DE2729842B2 (de) * 1977-07-01 1979-05-23 Skw Trostberg Ag, 8223 Trostberg Verfahren zur Herstellung von anorganischen Fasern auf Basis von Calciumsulfat
US4152408A (en) * 1977-11-25 1979-05-01 Certain-Teed Corporation Fibrous calcium sulfate
SE441457C (sv) * 1978-10-30 1990-06-07 Supra Ab Saett att framstaella slamma foer bestrykningsmedel foer papper, kartong och liknande, innehaallande kalciumsulfat som pigment
FI814197L (fi) * 1981-01-02 1982-07-03 Enriqueta Galceran Vila Foerfarande foer framstaellning och anvaendning av en kristallin produkt

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1962887A (en) * 1931-02-07 1934-06-12 American Cyanamid Co Method of controlling crystal size
US3594123A (en) * 1967-08-10 1971-07-20 Arizona Chem Enhancement of gypsum crystal growth in wet-process phosphoric acid
US3627485A (en) * 1968-11-05 1971-12-14 Nippon Kokan Kk Method of producing calcium sulfate dihydrate
US4270954A (en) * 1976-05-14 1981-06-02 Suddeutsche Kalkstickstoff-Werke Aktiengesellschaft Inorganic fibers
US4470877A (en) * 1981-05-13 1984-09-11 United States Gypsum Company Paper having calcium sulfate mineral filler for use in the production of gypsum wallboard

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0298120A4 *

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1989009187A1 (fr) * 1988-03-24 1989-10-05 Platres Lafarge S.A. Procede de preparation de sulfate de calcium a structure cristalline longiligne dotee d'une longueur et d'un facteur de forme maitrises
FR2640961A1 (fr) * 1988-12-22 1990-06-29 Lafarge Platres
EP0378837A1 (fr) * 1988-12-22 1990-07-25 Lafarge Coppee Préparation de sulfate de calcium dihydrate à structure cristalline longiligne
EP0663374A1 (fr) * 1994-01-14 1995-07-19 USG INTERIORS, Inc. Une composition pour dalle acoustique sans laine minérale
EP0692456A1 (fr) 1994-07-15 1996-01-17 Compania General Yesera, S.A. Procédé d'obtention d'une charge radiale, destinée en particulier à l'industrie papétière, charge obtenue formée de sulfate de calcium anhydre et hémihydrate et composition utile pour préparer cette charge
ES2095184A1 (es) * 1994-07-15 1997-02-01 Compania General Yesera S A Procedimiento para la obtencion de una carga radial especialmente para uso en la industria papelera, producto de carga formado por cocristalizacion de sulfatos de calcio anhidro y hemihidrato y composicion util para la preparacion de dicha carga.
WO2008092990A3 (fr) * 2007-02-02 2008-10-30 Kemira Oyj Produit de type gypse et procédé pour la préparation de celui-ci
WO2008092991A2 (fr) * 2007-02-02 2008-08-07 Kemira Oyj Procédé de fabrication de gypse
WO2008092990A2 (fr) * 2007-02-02 2008-08-07 Kemira Oyj Produit de type gypse et procédé pour la préparation de celui-ci
WO2008092991A3 (fr) * 2007-02-02 2008-11-06 Kemira Oyj Procédé de fabrication de gypse
JP2010517906A (ja) * 2007-02-02 2010-05-27 ケミラ オイ 石膏の製造方法
JP2010517905A (ja) * 2007-02-02 2010-05-27 ケミラ オイ 石膏生成物及びその製造方法
WO2010151499A1 (fr) * 2009-06-22 2010-12-29 Hercules Incorporated Revêtement à germe cristallin pour parement de panneau mural en gypse
CN102802935A (zh) * 2009-06-22 2012-11-28 赫尔克里士公司 用于石膏壁板贴面的晶种涂层
JP2012530854A (ja) * 2009-06-22 2012-12-06 ハーキュリーズ・インコーポレーテッド 石膏ウォールボードフェイシング用種結晶コーティング
WO2011098672A1 (fr) 2010-02-10 2011-08-18 Kemira Oyj Procédé pour la préparation d'un composite pigment‑fibre
WO2011141632A1 (fr) 2010-05-10 2011-11-17 Kemira Oyj Produit composite de gypse-fibre

Also Published As

Publication number Publication date
EP0298120A1 (fr) 1989-01-11
MX165337B (es) 1992-11-05
EP0298120A4 (fr) 1989-05-16
DK515588D0 (da) 1988-09-15
ATE86231T1 (de) 1993-03-15
ES2005755A6 (es) 1989-03-16
US4801355A (en) 1989-01-31
FI92047C (fi) 1994-09-26
DE3878756T2 (de) 1993-09-23
AU605576B2 (en) 1991-01-17
AU1496188A (en) 1988-08-10
DK515588A (da) 1988-11-01
FI884250A0 (fi) 1988-09-15
NO884146L (no) 1988-11-16
FI884250A (fi) 1988-09-15
NO884146D0 (no) 1988-09-16
NO175494C (no) 1994-10-19
FI92047B (fi) 1994-06-15
EP0298120B1 (fr) 1993-03-03
DE3878756D1 (de) 1993-04-08
DK171467B1 (da) 1996-11-11
NZ223170A (en) 1989-11-28
NO175494B (no) 1994-07-11
ZA88264B (en) 1988-07-01
CA1307903C (fr) 1992-09-29

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